Load lifting device



March 23, 1965 E. J. ALM 3,174,722

1.0m: 1.1mm; DEVICE Filed Sept. 17, 1962 3 h ets-Sheet 1 INVENTOR.ERHARD J. ALM

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Attorney March 23, 1965 E. J. ALM

LOAD LIFTING DEVICE 3 Sheets-Sheet 2 Filed Sept. 17, 1962 INVENTOR.ERHARD J. ALM 49, 44 s un A Home 1 March 23, 1965, J, L 3,174,722

LOAD LIFTING DEVICE Filed Sept. 1'7, 1962 3 Sheets-Sheet 3 INVENTOR.ERHARD J. ALM

Atfrnev i United rates This invention relates to improvements in devicesfor lifting and supporting loads and particularly for lifting andsupporting vehicles for inspection, repair, maintenance or for any otherpurpose.

The principal object of this invention is to provide a lift or hoist ofrelatively light-weight construction, readily movable from one locationto another and which does not require anchoring, but merely rests upon asupporting surface in the position selected to engage and lift the load.

Another important object is to provide a hoist which is collapsible intoa compact form readily disposable beneath a vehicle, and for storage,the hoist being easily manipulated thereunder to place it in the zoneappropriate for lifting and supporting the vehicle.

Still another object is to provide apparatus capable of developing powersufficient to raise quite heavy loads, quickly, over a determined rangeof adjustment; to provide apparatus which is safe; and further toprovide apparatus which can be manufactured economically.

Still another object of this invention is to provide a lift or hoistwhich incorporates integral means upon which it can be moved over asupport surface from one location to another.

The principal feature of this invention resides in providing aload-engaging platform formation which is supported from below uponextensible lever formations arranged in spaced parallel relation,operable contemporaneously by .a displaceable fluid pressure operatedmechanism to raise and lower the load-engaging platform formation, thelatter mechanism being mounted upon and extending between the extensiblelever formations only.

More particularly a very important feature resides in rigidly securingopposing like members of the extensible lever formations together toensure uniform extension, and hence horizontally of the load-engagingplatform.

Still another feature resides in employing a fluid-pressure-operatedmechanism in the form of an inflatable member of predeterminedconfiguration which inflatable member is constrained against ballooningunder inflation and has the characteristic of being extensiblesubstantially solely in a single direction, there being associated withthe inflatable member, opposing platform formations secured to theaforementioned extensible lever formations and clisplaceable therewithand adapted to bear against the ends of the cylindrical inflatablemember which, under inflation of the inflatable member, are forced apartto extend the extensible lever formations.

Another feature resides in providing casters mounted upon the leverformations which upon the collapse thereof depend below the extensiblelever formations to bear upon the supporting surface, the mounting ofthe casters being so arranged that the weight of the descending loadengaging platform formation and consequent com pact disposition of theplatform and lever formations moves the casters into contact with thesupporting surface, with the platform and lever formations being urgedupwardly of the casters and retained in that position by inter-engagingsupports carried by the lever formations resulting in the weight of theapparatus being taken solely by the casters.

These and other objects and features will be found in the followingspecification to be read in conjunction with the sheets of drawings inwhich:

FIGURE 1 is a perspective view of a hoist, conatent ice structed inaccordance with the invention, in the extended position.

FIGURE 2 is a side elevational view of the apparatus of FIGURE 1.

FIGURE 3 is a perspective view of the apparatus of FIGURE 1 in thecollapsed state.

FIGURE 4 is a vertical mid sectional view of the apparatus in thecollapsed state taken along lines 44 of FIGURE 3.

FIGURE 5 is a perspective view of the fluid pressureoperated expansiblecylinder of the apparatus of FIG- URE 1, with the extensible supportformation and loadengaging frame broken away and with a portion of thewall of the cylinder cut away.

FIGURE 6 is a perspective view of the safety mechanism employed with theapparatus of FIGURE 1.

Where understanding has not been impaired, in the followingspecification and drawings, the same numerals have been used todesignate parts of like function but of opposite symmetry for purposesof clarity.

In FIGURES l and 2 the hoist 10 is illustrated in the extendedload-supporting position. Hoist It consists of a load-engaging platformformation 11, uppermost, an extensible support formation 12, and afluid-pressure-operated mechanism 13 for extending or elevating thesupport formation 12.

Support formation 12 comprises essentially a first pair of steel I-beammembers 14 and a second pair of I-beam members 21, pivoted together onaligned pivots 20. The lower extremities of members 14 are hingedlyconnected as at 15 to a transversely extending base plate 16, and bracedlaterally adjacent to their lower ends by a channel member 17 andadjacent to their upper ends by a similar channel member 18.

Uppermost, as best seen in FIGURES 2 and 4, members 14 are provided withrollers 1 which are adapted to bear against a lower bearing surface ofthe loadengaging platform 11 as will be explained.

Members 21, likewise, are provided with lower brace members 22 and upperbrace members 23, each of which consist of intermediate channel portions24, 25, and outer channel portions 26, 27, respectively, channelportions 26 opening upwardly and channel portions 27 opening downwardlyto receive the adjacent sections of members 14- when the hoist iscollapsed into the form shown in FIG- URES 3 and 4.

Members 21 are each provided, adjacent to their upper ends, with a rigidplate 28 extending axially which is pivotally connected as at 29 to theload-engaging platform 11 as best seen in FIGURE 2.

Members 21 are provided at their lower ends with surface-engagingrollers 30 mounted on suitable pivots 31. Connected by each of thepivots 31 to the members 21 and located outwardly thereof is a pair ofelongated rack members 32 which extend longitudinally of the hoist lil,the opposite ends thereof being located within a channel shaped guideformations 33, located at each end of base plate 16 and immediatelyadjacent the lower ends of the members 14.

Mounted on pivot 33a to extend between the walls of each of thechannel-shaped guide formations 33 is a pawl 34, swingable to engage inteeth 35 of each rack 32, the teeth and pawl being configured such thatupon extension of the members 14 and 21 upwardly, the pawl rides overthe teeth 35, with the racks 32 moving in the direction of the arrow100. As shown in FIGURE 6, the pawl 34 will positively engage the teeth35 in sequence preventing withdrawal of the rack. As will be readilyunderstood, this provides an automatic safety device to preventcollapse, should the fluid pressure-operated mechanism 13 fail.

An extension spring 36 is connected between the base plate 16 and adisplaceable cylinder 37a of a fluid pressure-operated piston andcylinder device 37 which is mounted upon base plate 16. The displaceablecylinder 37a is fixedly connected by an arm 37!) to pawl 34. Upondelivery of fluid under pressure by way of the hose connection 38a froma suitable source to the piston and cylinder device 37, the cylinder 37ais moved upwardly and hence the pawl 34 is released from the rack teeth35, whereupon rack 32 is free to be displaced in channel 33 in thedirection of arrow 101, to permit the descent of the support formation12.

The hose connections 38a for each of the piston and cylinder devices 37are connected to a common conduit 38b leading to a source of fluid underpressure.

Referring particularly to FIGURES 1, 2 and 5, the fluid pressureoperated device 13 for extending the support formation 12 comprises alower platform 39, an upper platform 40 and a cylindrical inflatablecollapsible member 47 Each of the platforms 39, 40 consist of a mainsteel plate 41, 42 respectively, have integral flange formations 43, 44and are reinforced with peripherally arranged plates 45, 46 disposed inangled relation to the main steel plates 41 and 42 and the flangeformations 43, 44 respectively, and connected thereto as by welding, theforegoing arrangement defining a dish-shaped configuration for thereception of the ends of the member 47.

It is to be appreciated that the inflatable member 47 comprises in thepreferred embodiment an inner cylindrically shaped vulcanized rubbercasing 43 having an outer sheath or casing 49 of fabric which isflexible and substantialy non-extensible to maintain the cylindricalconfiguration under inflation.

In one embodiment of the invention the inner vulcanized rubber casing'48is constructed from material having inch thickness 7 to of an inch); Theouter casing 49 comprises three layers of synthetic woven fabric knownin association with the trademark Terylene 1100 denier with a tensilestrength of approximately 700 lbs. per square inch.

Inflatable member 47 of the foregoing construction in one embodiment hasa diameter of the order of 20 inches and an axial extent under inflationof the order of 16 inches which when fully inflated exerts a pressure of65 to 70 lbs. per square'inch, more or less, capable of lifting a loadof 5000 lbs., which approximates the weight of a heavier vehicle, theaverage vehicle having a weight of 3500 lbs.

The end walls of the inflatable member 47 are secured. to the underlyingand overlying platforms 39 and 40 by 7 suitable fasteners 50, theopenings through the walls of member 47 and receiving the fasteners t)being sealed in a suitable manner.

Inflatable member 47 is provided with an integral tubular portion 51 forpassing fluid under pressure thereinto, and for the escape of fluidunder pressure therefrom, the tubular portion 51 being connected to ahose 51a leading to a source of fluid pressure.

Lower platform 39 of mechanism 13 is connected by a pair of spaced hingeformations 52 to channel member 17 bracing the inner members 14, withplatform 39 having recesses remote from the hinges 52 and on oppositesides to provide bearing surface formations 53, each of which is adaptedto be engaged by a roller bearing 54, carried by and extending inwardlyof channel portions 26 (FIGURE 1).

Likewise, the upper platform 40 is supported by spaced hinge formations55 from channel portions'25 of brace members 21, while remote from thehinges 55 at opposite sides of the upper platform 40 recesses areprovided to define bearing surfaces 57 which are adapted to be engagedby roller bearings 56 carriedby and extending inwardly of the I-beammembers 14.

As best seen in FIGURES 2 and 4, L-shaped flanges 58 are secured inspaced relation by welding to the lower transverse channel member 17andthe channel portion 24 of the lower transverse brace 22 of thesupport formation 12. Flanges 58 carry pivotal depending lugs 59 betweenwhich wheels or casters 60 are mounted and upon which the apparatus isadapted to be supported for transport.

Load engaging platform formation 11 consists essentially oflongitudinally extending angle members 61 at each side and transverselyextending channel members 62 at each end, the angle members 61 having ateach end a plate 63 of extended area, which plate is provided with adepending flange or apron 64 therearound. As seen in FIGURES 2 and 4,the lower surfaces of plates 63 as at A constitute bearing surfaceformations against which rollers 19 carried by the members 14 bear withthe extension of the members 14, 21 upwardly to engage and lift the loadsupported upon the platform formation 11. The depending flange or apron64 houses both the roller 19 and the pivot connection 29 at the'oppositeend, and as well serves as a stop or locating means for the rollers 19.

Mounted flatwise upon the upper surface of the plate 63 are extensionplates 66 supported for swinging movement about a vertical central pivot67 to accommodate the frame of a vehicle, so that adequate support willbe given. 7

It is to be observed from FIGURE 4 that the wheels or casters 60, withthe apparatus in a collapsed state depend below the framework, thecasters 60 being offset from the'axis of pivot 20 of the members 14 and21 such that upon the descent of the support formation and theload-engaging frame the members 14 and 21 are located above thesupporting surface. Furthermore, it is seen that the inner members 14and outer members 21 are maintained in coplanar relation by reason ofthe channel portions 26, 27, serving as a stop against further descent.

It is now convenient to describe the operation of the device. Firstly,the apparatus as shown in FIGURE 3 in the collapsed state will be placedbeneath the load to be hoisted, and by reason of the casters 60 can berolled thereunder, if possible, and manipulated so that the proper zonewill be engaged.

Controlling the application of pressure fluid to the inflatable member47 will be a three-way valve mechanism, one position for directingpressure fluid to the member 47 from a suitable source, a secondposition which is neutral, and a third position to connect theinflatable member to the atmosphere to permit the member 47 to beemptied, so that the apparatus can be col-lapsed.

In the case of the preferred embodiment, when vehicles up to 5000 lbs.are to be lifted, it is necessary to develop approximately .to lbs.pressure per square inch in the member 47, having the specifications 20inches in diameter and an axial extent of the order of 16 inches.Normally, a source of fluid pressure, for example compressed air, atlbs. per square inch would be used.

Compressed .air is then. directed through the conduit 51a in tubularportion 5-1 to the inflatable member 47. From the collapsed position tothe extended position the rack 32 can be displaced in the direction ofthe arrow with the pawl 34 riding over and engaging in the teeth 35. .Asinflation proceeds, because the inflatable member 47 'is extensiblesubstantially solely in the vertical direction, the platform formations39 and 46 are forced apart, the lower platform 39 swinging on the hinges52 and urged downwardly by the expansion of the member 47 to maintainits bearing surfaces 54 against roller bearings 55 at each side, andlikewise the upper platform formation 49 swinging about its hinges 55 tomaintain the bearings surfaces 57' against the roller bearings -56,

In this manner the extension of the inflatable member 47 is continuouslytransmitted to the members 14 and 21 causing them to swing about theircommon pivots 20, which r-esults in the upward displacement of theloadengaging platform 11.

As will be readily appreciated from the drawings, the

members 14 swing about the lower pivots 15 carried by the base plate 16,and because of the upward displacement of the members 21 swinging on thepivots 2d, the lower end of the members 21 are displaced towards thebase plate 16 and roll upon the rollers 30. This is accompanied bydisplacement of the racks 32 through the channel formation 33 and theconsequent engagement of the teeth 35 by pawl 34 to maintain theextended position.

Likewise, with the displacement upwardly of the members 14, rollers 19are displaced to the right as seen in FIGURE 2 and bear against theunder surfaces as at A of the plates es.

It will be appreciated that the overlying platform formations 39 and 4dare maintained in substantial vertical registration by the reason of thehinged connections and roller bearing surface formations. Therefore theinflatable member 47 experiences no appreciable distor tion throughoutthe range of extended positions.

In the drawings it is seen that roller bearings 55 and 56 have limitpositions with respect to their hearing surface formations which isdictated by the upstanding wall formations 63 and 69 respectively. This,however, is variable.

When it is desired to lower the hoist, firstly the pawls 34 are releasedfrom the teeth 35 of racks 32 by transmitting fluid-under-pressure topiston and cylinder mechanisms 37 which lifts the pawls 34, permittingthe racks 32 to be withdrawn from the channel formations 33.

Then the three-way valve mechanism is operated to connect the inflatablemember 47 to the atmosphere to permit the inflatable member 47 to beemptied of pressure fluid, the weight of the load assisting in itsescape.

Upon the collapse of the support formation 12 it will be seen in FIGURE3 that the channel portions 27 embrace the adjacent portions of theinner members 14, :and likewise the channel portions 26 are adapted toembrace the portions of the inner members 14 so that a planarity of thecomponents may be achieved, and casters 60 rest upon the supportingsurface.

Furthermore, it is to be appreciated that the dishshaped configurationof the overlying platforms 39 and 40, against which the ends of theinflatable member 47 bear, serve as a receptacle for the collapsedinflatable member 47, assisting in achieving the planarity desired.

As shown in FIGURES 1 and 3 particularly, the deending flange or apronE- of the load-engaging frame 1-1 is provided with openings 70therethrough to accommodate the air hose sections 33a leading to thepiston and cylinder devices 37, to achieve the horizontal registrationand desired planarity.

What I claim is:

1. In a load lifting apparatus including a load-engaging frame and aground-engaging frame and two pairs of hinged levers connected betweensaid frames one pair on each side thereof, a first one of each of saidpairs of levers being corresponding and a second one of each of saidpairs of levers being corresponding, the improvement comprising: a firstplatform hingedly connected between said corresponding first levers andmov ably connected to said corresponding second levers; a secondplatform hingedly connected to said second corresponding levers in aspaced apart relationship from said first platform connections theretoand movably connected to said first corresponding levers in a spacedapart relationship from said first platform connection thereto, andfluid inflatable means constrained to expand substantially verticallysecured between said first and second platforms.

2. A load lifting apparatus including a load-engaging frame and aground-engaging frame and means for raising said load en gagi-ng framerelative to said groundengaging frame said means comprising: a firstlever and a second lever on each side and extending betweencorresponding sides of said frames, said levers being pivotallyconnected one to the other intermediate their ends; said first leverseach being pivotally connected at a lower end to said ground-engagingframe and at an upper end to said load-engaging frame, said secondlevers being movable connected at an upper end to said load-engagingplatform and movably connected at a lower end to said ground-engagingframe; a first platform movably connected between said second levermembers, and pivotally connected :between said first lever members, anda second platform secured between said lever members in a spaced apartrelationship from said first platform; said second platform beingpivotally connected to said first lever members and movably connected tosaid second lever members, and an inflatable bag constrained to extendsubstantially in a vertical direction secured between said first andsecond platform members.

3. Apparatus as claimed in claim 1 wherein said infiatable meanscomprises a casing having a generally cylindrical configuration.

4. Apparatus according to claim 3 wherein said cylindrical casing isdefined by an axially extending and end walls of flexible extensiblematerial, and inflatable over a predetermined range of pressures, andmeans associated with said axially extending and end walls constrainingsame against extension over said predetermined range of pressures.

5. Apparatus as claimed in claim 1 wherein said connections of first andsecond platforms to said levers are spaced inward of the ends thereof.

6. Apparatus as claimed in claim 1 wherein said loadenga-ging framecomprises a pair of side members and a pair of transverse membersextending between and rigidly secured to opposed ends of said sidemembers to define an area exceeding the area of said ground-engagingframe.

7. Apparatus as claimed in claim 1 including lock means for securingsaid load-engaging platform in a fixed elevation relative to saidground-engaging platform.

8. Apparatus as claimed in claim 1 including wheel means mounted in afixed relationship to said first corresponding levers and wheel meansmounted in a fixed relationship to said second corresponding levers.

9. Apparatus as claimed in claim 8 wherein said first lever membersinclude Wheel means mounted adjacent a ground-engaging end thereof.

References Cited by the Examiner UNITED STATES PATENTS 1,859,830 5/32Kummel 254-422 2,001,744 5/35 Patterson.

2,495,092 1/50 Cox et a1 254-93 2,609,177 9/52 Hughes.

2,610,824 9/52 Grier 254-122 2,843,418 7/58 Gray 254l22 X WILLIAMFELDMAN, Primary Examiner.

1. IN A LOAD LIFTING APPARATUS INCLUDING A LOAD-ENGAGING FRAME AND AGROUND-ENGAGING FRAME AND TWO PAIRS OF HINGED LEVERS CONNECTED BETWEENSAID FRAMES ONE PAIR OF EACH SIDE THEREOF, A FIRST ONE OF EACH OF SAIDPAIRS OF LEVERS BEING CORRESPONDING AND A SECOND ONE OF EACH OF SAIDPAIRS OF LEVERS BEING CORRESPONDING, THE IMPROVEMENT COMPRISING: A FIRSTPLATFORM HINGEDLY CONNECTED BETWEEN SAID CORRESPONDING FIRST LEVERS ANDMOVABLY CONNECTED TO SAID CORRESPONDING SECOND LEVERS; A SECOND PLATFORMHINGEDLY CONNECTED TO SAID SECOND CORRESPONDING LEVERS IN A SPACED APARTRELATIONSHIP FROM SAID FIRST PLATFORM CONNECTIONS THERETO AND MOVABLYCONNECTED TO SAID FIRST CORRESPONDING LEVERS IN A SPACED APARTRELATIONSHIP FROM SAID FIRST PLATFFORM CONNECTION THERETO, AND FLUIDINFLATABLE MEANS CONSTRAINED TO EXPAND SUBSTANTIALLY VERTICALLY SECUREDBETWEEN SAID FIRST AND SECOND PLATFORMS,